Mechanical time fuse structure



June 3, 1947. B. B. PATTON 2,421,390

' MECHANICAL TIME FUSE STRUCTURE Filed March 7, 1939 Pig 4 Een'umh-L Elf nttun 4 E33,: ZE/WM,

Patented June 3, 1947 MECHANICAL TIME FUSE STRUCTURE Benjamin B. Patton, Philadelphia, Pa, assignor to the United States of America, as represented by the Secretary of War Application March 7, 1939, Serial No. 260,313

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757

1 Claim.

This invention relates to mechanical time fuse I structure more particularly to a safety device positively operable to lock the escapement ofthe timing mechanism until such time as the fuse may be set.

It is a common-place practice in the art to employ means to lock the escapement of the clockwork timing mechanism against movement that might be initiated due to shock received in transportation or handling. In the case where the fuse is to be utilized on a time delay explosive missile propelled from a piece of ordnance which imparts relative high rotational velocity to the missile the problem of a suitable safety device is comparatively simple, for a spring of suificient stiffness to withstand any shock of ordinary handling may be used in the safety and still be rendered inoperative for the purpose by the relative high degree of centrifugal force developed. However, quite another problem is presented in those instances where the fuse is employed on an explosive missile projected from a piece of ordnance imparting relatively low rotational velocity to the missile, for if a spring of sufficient stiffness be employed in the safety device to render the fuse safe against malfunctioning owing to shocks received in handling, it will be too stiff to be rendered inoperative by the relatively low centrifugal force developed upon projection of the missile from the ordnance piece.

It is an object of this invention to provide a simple, yet efficient and positive device for lock ing the escapement of the timing mechanism of a mechanical fuse against initiation of operation due to the chance or accidental occurrence of shock suflicient to initiate such action in the course of handling explosive missiles armed with the fuse.

It is a further object of the invention to provide a safety device for locking the escapement of the timing mechanism of a mechanical time fuse which is particularly adapted for use on explosive missiles in which relative low centrifugal force is developed upon propulsion of the missile.

It is a still further object of the invention to provide a safety device for locking the escapement of the timing mechanism of a mechanical time fuse that may be interchangeably used with equal efiiciency on explosive missiles in which either relative low or high centrifugal force is developed.

The specific nature of the invention as Well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawingsin which:

:Figure 1 is a vertical sectional view partly in side elevation of ;the mechanical time fuse structure;

Figure '2 is ,a horizontal sectional view of the same taken substantially along a plane as indicated by the'Z-eZ of Fig. 1;

Figure '3 is a fragmentary horizontal sectional view of the. fuse structure taken on substantially the same plane as :Fig. 2, showing certain parts in their displaced-positions; and

Figure 4 is anenlarged side elevational View, partly in section, ofa portion of the structure.

Referring .to thedrawings wherein like characters of reference refer to like parts throughout the views there is shown a portion of a fuse casingincludinga base-element [2 having a stepped cylindrical recess 16 and cap portion or setting member illtelescopically arranged within the recess 6 for relativerotational movement with the base. A timing unit generally indicated at [3, such as a clockwork mechanism, is housed ithin the casing and associated with the base so as to be movable therewith. A bottom supportin plate or member I, comprising one of several such plates disposed in superposed relation to forma supporting structurefor-the clockwork, is secured to the base l2.

A safety device generally indicated at 2 is shown in Fig. 2 as comprising a locking lever 3 pivoted for rotation on member I through impressed centrifugal force, from a position where the weighted projection 4 engages and prevents oscillation of the escapement balance or lever A of the associated clockwork, to a position ineffective for the purpose as more particularly disclosed in the co-pending application of Eugene J. Fix, Serial No, 260,311, filed on even date herewith.

The safety device 2 also includes a cantilever spring 5 of a character that will permanently set in predetermined deflected position connected to the supporting plate or member I near its periphery at 6, and having a suitably formed free terminal 1, adapted in operative position to engage the spring abutment 8 on looking lever 3 to supplement the action of the clockwork in restraining the locking lever 3 in looking position all as clearly shown and described in the above mentioned co-pending application,

As the safety device of this invention is into handling. To the end that a spring of such 7 character that it may be deflected from operative position shown in Fig. 2 to a position outwardly of plate I, or inoperative position as shown'in Fig. 3, by th comparatively low developed centrifugal force of the fuse in flight and yet be effective to retain the locking lever 3 in locking position in the zero or safe setting of the fuse an element 9 is provided to prevent outward movement of the spring in zero position of the fuse.

The element 9 may comprise a suitable lug secured to the lower edge of the rotatable fuse setting cap member 19. In the zero or safe position of the setting member 19 the lug 9 is interposed between the terminal "I of spring 5 and the outer defining wall of a groove ll formed by the lower edge of the cap setting member l0 and step I! in the base [2 in such manner as to abut the terminal of the spring and prevent movement thereof into groove I l to release locking lever 3.

In the displaced position of lug 9 relative to, the terminal I of spring 5, as shown in Fig. 3, the spring 5 will be free to deflect into the groove ll under centrifugal force to release locking lever 3 for rotation. In order to provide the fuse with a minimum time setting the terminal 1 of spring 5 or diameter of lug 9 or both may be so arranged as to compel rotation of the setting cap I0, which carries the lug 9, to the minimum time setting desired before the spring terminal I may move into the groove ll clear of lug 9.

In Fig. 4 the lug 9 is shown as being inserted in a recess l4 formed in the lower edge of the setting cap member ID, and retained in position by a shank l5 frictionally or otherwise suitably secured in a corresponding counterbore in member Ill. Although this method of securing the lug to the setting member is at present preferred it is to be understood that a dependent member of any suitable type and integral with or secured in any suitable inannerto the setting member I!) may be used;

Having now particularly described this inven- 4 tion and what at present appears to me as a preferred embodiment what I claim and desire to secure by U. S. Letters Patent is:

A fuse comprising a casing, said casing including a base and an element rotatably mounted on the base, a housing supported by and fixed relatively to the base, an escapement balance in said housing, a, centrifugally actuated locking lever mounted in said housing and normally engaging the escapement balance to prevent oscillation thereof, said lever being movable by centrifugal force to an inoperative position out of engagement with the escapement balance, a spring fixed at one end to the housing, the opposite, free end of the spring being bent outwardly and back upon itself to form a detent portion normally disposed in yieldable engagement with a portion of the locking lever to hold the locking lever in engagement with the escapement balance, said detent portion being urged outwardly by centrifugal force, against the resiliency of the spring to release the locking lever, and a rigid, positive locking member carried by the rotatable element of the casing and disposed, when in an operative position, to engage the terminal part of the detent portion to positively retain the detent portion in engagement with the locking lever, said rotatable element being movable to move the positive locking member to an inoperative position out of engagement with the detent portion, to permit the detent portion and locking lever to function normally in response to centrifugal force.

BENJAMIN B. PATTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 7 Name Date 1,003,078 Wieser "Sept. 12, 1911 1,311,837 Ohlson July 29, 1919 1,069,094 Junghans July 29, 1913 FOREIGN PATENTS Number Country Date 264,755 Germany Sept. 29, 1913 284,968 Great Britain Feb. 9, 1928 285,553 Great Britain Feb. 16, 1928 

